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    <title>zpbutt</title>
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    <center>Scilab Function</center>
    <div align="right">Last update : 20/12/2004</div>
    <p>
      <b>zpbutt</b> -  Butterworth analog filter</p>
    <h3>
      <font color="blue">Calling Sequence</font>
    </h3>
    <dl>
      <dd>
        <tt>[pols,gain]=zpbutt(n,omegac)  </tt>
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    <h3>
      <font color="blue">Parameters</font>
    </h3>
    <ul>
      <li>
        <tt>
          <b>n</b>
        </tt>: integer (filter order)</li>
      <li>
        <tt>
          <b>omegac</b>
        </tt>: real (cut-off frequency in Hertz)</li>
      <li>
        <tt>
          <b>pols</b>
        </tt>: resulting poles of filter</li>
      <li>
        <tt>
          <b>gain</b>
        </tt>: resulting gain of filter</li>
    </ul>
    <h3>
      <font color="blue">Description</font>
    </h3>
    <p>
    computes the poles of a Butterworth analog
    filter of order <tt>
        <b>n</b>
      </tt> and cutoff frequency omegac
    transfer function H(s) is calculated by <tt>
        <b>H(s)=gain/real(poly(pols,'s'))</b>
      </tt>
    </p>
    <h3>
      <font color="blue">Author</font>
    </h3>
    <p>F. Delebecque INRIA</p>
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